Adaption and validation of the adherence barriers questionnaire for HIV patients on antiretroviral therapy (ABQ-HIV)
Background: Despite substantial advances in antiretroviral therapy (ART) for human immunodeficiency virus (HIV) in the last decades, non-adherence (NA) continues to be a major challenge in real-life treatment. To meet this challenge, adherence-promoting interventions with a tailored approach towards patient-specific adherence barriers identified using a reliable and practicable questionnaire are needed. This investigation aimed to develop and validate a respective questionnaire (Adherence Barriers Questionnaire for HIV: ABQ-HIV) based on an earlier version of the ABQ.
Methods: The existing ABQ was discussed by an expert panel and revised according to the specifications of ART therapy for HIV patients. Initially, the ABQ-HIV consisted of 17 items formulated as statements (4-point-Likert-scale ranging from “strongly agree” to “strongly disagree”). A higher score indicates a higher influence of a specific barrier on patient’s perceptions. The ABQ-HIV was applied in a cross-sectional survey of German HIV patients. Evaluation of the questionnaire included an assessment of internal consistency as well as factor analysis. Convergent validity was assessed by comparing the ABQ-HIV score with the degree of self-reported adherence measured by the 8-item Morisky Medication Adherence Scale (MMAS-8©).
Results: Three hundred seventy patients were able to be included in all validation analyses. The included patients had a mean age of 51.2 years, and 15.7% were female. The mean HIV infection time was 11.7 years, and the mean duration of treatment since first starting ART was 8.7 years. Twenty-five patients – excluded from all further analyses - were not able/willing to answer all ABQ-HIV questions. The reliability analysis results showed a Cronbach’s α of 0.708 for the initial 17 items in the ABQ-HIV draft. Two items were eliminated from the initial questionnaire, resulting in a Cronbach’s α of 0.720 and a split-half reliability of 0.724 (Spearman–Brown coefficient). Based on the reduced 15-item scale, the factor analysis resulted in three different components of the questionnaire.
The score of the reduced 15-item ABQ-HIV scale and the scores of the three subscales correlated significantly with the MMAS score. All correlation coefficients were negative, indicating that higher burdens of adherence barriers measured by ABQ-HIV or its subscales were associated with a lower MMAS score and, thus, a lower adherence level.
The ROC analysis using the MMAS low adherence classification as its state variable provided a cut-off for the ABQ-HIV scale of > 28 (sensitivity: 61.5%, specificity: 83.3%). In our sample, 85 patients (23.0%) reached a score of > 28 and appeared to face a high non-adherence risk.
Conclusions: The ABQ-HIV is a practical, reliable, and valid instrument for identifying patient-specific barriers to adherence to HIV treatment. It is also useful in identifying HIV patient subgroups according to adherence barriers specific to these patients.
